sysdeps/unix/sysv/linux/internal_statvfs.c

   1 /* Copyright (C) 1998-2006, 2010 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <assert.h>
  21 #include <errno.h>
  22 #include <mntent.h>
  23 #include <paths.h>
  24 #include <stdbool.h>
  25 #include <stdio_ext.h>
  26 #include <string.h>
  27 #include <sys/mount.h>
  28 #include <sys/stat.h>
  29 #include <sys/statfs.h>
  30 #include <sys/statvfs.h>
  31 #include "linux_fsinfo.h"
  32 #include "kernel-features.h"
  33
  34
  35 /* Special internal-only bit value.  */
  36 #define ST_VALID 0x0020
  37
  38
  39 #ifndef STATFS
  40 # define STATFS statfs
  41 # define STATVFS statvfs
  42 # define INTERNAL_STATVFS __internal_statvfs
  43
  44
  45 # ifndef __ASSUME_STATFS_F_FLAGS
  46 int
  47 __statvfs_getflags (const char *name, int fstype, struct stat64 *st)
  48 {
  49   if (st == NULL)
  50     return 0;
  51
  52   const char *fsname = NULL;
  53   const char *fsname2 = NULL;
  54   const char *fsname3 = NULL;
  55
  56   /* Map the filesystem type we got from the statfs call to a string.  */
  57   switch (fstype)
  58     {
  59     case EXT2_SUPER_MAGIC:
  60       fsname = "ext4";
  61       fsname2 = "ext3";
  62       fsname3 = "ext2";
  63       break;
  64     case DEVPTS_SUPER_MAGIC:
  65       fsname= "devpts";
  66       break;
  67     case SHMFS_SUPER_MAGIC:
  68       fsname = "tmpfs";
  69       break;
  70     case PROC_SUPER_MAGIC:
  71       fsname = "proc";
  72       break;
  73     case USBDEVFS_SUPER_MAGIC:
  74       fsname = "usbdevfs";
  75       break;
  76     case AUTOFS_SUPER_MAGIC:
  77       fsname = "autofs";
  78       break;
  79     case NFS_SUPER_MAGIC:
  80       fsname = "nfs";
  81       break;
  82     case SYSFS_MAGIC:
  83       fsname = "sysfs";
  84       break;
  85     case REISERFS_SUPER_MAGIC:
  86       fsname = "reiserfs";
  87       break;
  88     case XFS_SUPER_MAGIC:
  89       fsname = "xfs";
  90       break;
  91     case JFS_SUPER_MAGIC:
  92       fsname = "jfs";
  93       break;
  94     case HPFS_SUPER_MAGIC:
  95       fsname = "hpfs";
  96       break;
  97     case DEVFS_SUPER_MAGIC:
  98       fsname = "devfs";
  99       break;
 100     case ISOFS_SUPER_MAGIC:
 101       fsname = "iso9660";
 102       break;
 103     case MSDOS_SUPER_MAGIC:
 104       fsname = "msdos";
 105       break;
 106     case NTFS_SUPER_MAGIC:
 107       fsname = "ntfs";
 108       break;
 109     case LOGFS_MAGIC_U32:
 110       fsname = "logfs";
 111       break;
 112     case BTRFS_SUPER_MAGIC:
 113       fsname = "btrfs";
 114       break;
 115     case CGROUP_SUPER_MAGIC:
 116       fsname = "cgroup";
 117       break;
 118     }
 119
 120   FILE *mtab = __setmntent ("/proc/mounts", "r");
 121   if (mtab == NULL)
 122     mtab = __setmntent (_PATH_MOUNTED, "r");
 123
 124   int result = 0;
 125   if (mtab != NULL)
 126     {
 127       bool success = false;
 128       struct mntent mntbuf;
 129       char tmpbuf[1024];
 130
 131       /* No locking needed.  */
 132       (void) __fsetlocking (mtab, FSETLOCKING_BYCALLER);
 133
 134     again:
 135       while (__getmntent_r (mtab, &mntbuf, tmpbuf, sizeof (tmpbuf)))
 136         {
 137           /* In a first round we look for a given mount point, if
 138              we have a name.  */
 139           if (name != NULL && strcmp (name, mntbuf.mnt_dir) != 0)
 140             continue;
 141           /* We need to look at the entry only if the filesystem
 142              name matches.  If we have a filesystem name.  */
 143           else if (fsname != NULL
 144                    && strcmp (fsname, mntbuf.mnt_type) != 0
 145                    && (fsname2 == NULL
 146                        || strcmp (fsname2, mntbuf.mnt_type) != 0)
 147                    && (fsname3 == NULL
 148                        || strcmp (fsname3, mntbuf.mnt_type) != 0))
 149             continue;
 150
 151           /* Find out about the device the current entry is for.  */
 152           struct stat64 fsst;
 153           if (stat64 (mntbuf.mnt_dir, &fsst) >= 0
 154               && st->st_dev == fsst.st_dev)
 155             {
 156               /* Bingo, we found the entry for the device FD is on.
 157                  Now interpret the option string.  */
 158               char *cp = mntbuf.mnt_opts;
 159               char *opt;
 160
 161               while ((opt = strsep (&cp, ",")) != NULL)
 162                 if (strcmp (opt, "ro") == 0)
 163                   result |= ST_RDONLY;
 164                 else if (strcmp (opt, "nosuid") == 0)
 165                   result |= ST_NOSUID;
 166                 else if (strcmp (opt, "noexec") == 0)
 167                   result |= ST_NOEXEC;
 168                 else if (strcmp (opt, "nodev") == 0)
 169                   result |= ST_NODEV;
 170                 else if (strcmp (opt, "sync") == 0)
 171                   result |= ST_SYNCHRONOUS;
 172                 else if (strcmp (opt, "mand") == 0)
 173                   result |= ST_MANDLOCK;
 174                 else if (strcmp (opt, "noatime") == 0)
 175                   result |= ST_NOATIME;
 176                 else if (strcmp (opt, "nodiratime") == 0)
 177                   result |= ST_NODIRATIME;
 178                 else if (strcmp (opt, "relatime") == 0)
 179                   result |= ST_RELATIME;
 180
 181               /* We can stop looking for more entries.  */
 182               success = true;
 183               break;
 184             }
 185         }
 186       /* Maybe the kernel names for the filesystems changed or the
 187          statvfs call got a name which was not the mount point.  Check
 188          again, this time without checking for name matches first.  */
 189       if (! success && (name != NULL || fsname != NULL))
 190         {
 191           if (name != NULL)
 192             /* Try without a mount point name.  */
 193             name = NULL;
 194           else
 195             {
 196               /* Try without a filesystem name.  */
 197               assert (fsname != NULL);
 198               fsname = fsname2 = fsname3 = NULL;
 199             }
 200
 201           /* It is not strictly allowed to use rewind here.  But
 202              this code is part of the implementation so it is
 203              acceptable.  */
 204           rewind (mtab);
 205
 206           goto again;
 207         }
 208
 209       /* Close the file.  */
 210       __endmntent (mtab);
 211     }
 212
 213   return result;
 214 }
 215 # endif
 216 #else
 217 extern int __statvfs_getflags (const char *name, int fstype,
 218                                struct stat64 *st);
 219 #endif
 220
 221
 222 void
 223 INTERNAL_STATVFS (const char *name, struct STATVFS *buf,
 224                   struct STATFS *fsbuf, struct stat64 *st)
 225 {
 226   /* Now fill in the fields we have information for.  */
 227   buf->f_bsize = fsbuf->f_bsize;
 228   /* Linux has the f_frsize size only in later version of the kernel.
 229      If the value is not filled in use f_bsize.  */
 230   buf->f_frsize = fsbuf->f_frsize ?: fsbuf->f_bsize;
 231   buf->f_blocks = fsbuf->f_blocks;
 232   buf->f_bfree = fsbuf->f_bfree;
 233   buf->f_bavail = fsbuf->f_bavail;
 234   buf->f_files = fsbuf->f_files;
 235   buf->f_ffree = fsbuf->f_ffree;
 236   if (sizeof (buf->f_fsid) == sizeof (fsbuf->f_fsid))
 237     buf->f_fsid = ((fsbuf->f_fsid.__val[0]
 238                     & ((1UL << (8 * sizeof (fsbuf->f_fsid.__val[0]))) - 1))
 239                    | ((unsigned long int) fsbuf->f_fsid.__val[1]
 240                       << (8 * (sizeof (buf->f_fsid)
 241                                - sizeof (fsbuf->f_fsid.__val[0])))));
 242   else
 243     /* We cannot help here.  The statvfs element is not large enough to
 244        contain both words of the statfs f_fsid field.  */
 245     buf->f_fsid = fsbuf->f_fsid.__val[0];
 246 #ifdef _STATVFSBUF_F_UNUSED
 247   buf->__f_unused = 0;
 248 #endif
 249   buf->f_namemax = fsbuf->f_namelen;
 250   memset (buf->__f_spare, '\0', sizeof (buf->__f_spare));
 251
 252   /* What remains to do is to fill the fields f_favail and f_flag.  */
 253
 254   /* XXX I have no idea how to compute f_favail.  Any idea???  */
 255   buf->f_favail = buf->f_ffree;
 256
 257 #ifndef __ASSUME_STATFS_F_FLAGS
 258   if ((fsbuf->f_flags & ST_VALID) == 0)
 259     /* Determining the flags is tricky.  We have to read /proc/mounts or
 260        the /etc/mtab file and search for the entry which matches the given
 261        file.  The way we can test for matching filesystem is using the
 262        device number.  */
 263     buf->f_flag = __statvfs_getflags (name, fsbuf->f_type, st);
 264   else
 265 #endif
 266     buf->f_flag = fsbuf->f_flags ^ ST_VALID;
 267 }